The single-cable distribution technologies described herein relate generally to television signal delivery techniques. These techniques enable satellite broadcast programming to be distributed to multiple users over a single plastic optical fiber (POF), coaxial cable, or the like. These single-cable techniques also eliminate the numerous cables that would otherwise be required to support multiple consumer electronic devices, referred to herein as integrated receiver/decoders (IRDs). IRDs convert radio-frequency signals to a form that can be used in content displays, or the like. IRDs include, for example, television tuner-receivers, single or twin tuner digital video recorders (DVRs), television receivers, single or multiple set-top boxes (STBs), servers that distributes video signals to client boxes that feed display devices, or the like. The term IRD is intended to refer to any such device, regardless of any additional capabilities that it may have, such as recording television content, delaying the display of broadcasts, enabling WiFi communications, or the like. The term applies regardless of the location of the device, such as on top of, below, or beside a television set or other display device, embedded within the television set or other display device, or the like.
Single-cable distribution technology is finding widespread use in satellite television signal delivery. Without single-cable distribution, providing full spectrum access for multiple receivers or receivers with multiple tuners in a single family home has required separate cables feeding respective IRDs from satellite antenna equipment. Such satellite equipment is commonly referred to as an outdoor unit (ODU).
Typical ODUs include: (1) a parabolic dish or reflector; and (2) a low-noise block (LNB) mounted on the feed of the dish. The LNB may include an RF front-end, a multi-switch, and/or other signal processing and distribution equipment. Alternatively, the multi-switch and at least some of signal processing and distribution equipment may reside in a module that is distinct remote the LNB. The parabolic dish directs satellite microwave signals on which multiple television signals are encoded into the RF front end. These signals are encoded with multiple television signals over a very wide bandwidth. It should be noted that the term “ODU” is denotes outdoor satellite antenna equipment. However, the physical location of the ODU need not be outdoors. Furthermore, the ODU need not comprise traditional satellite television equipment, but may include other types of microwave frequency and/or wide bandwidth radio frequency (RF) signal receiving equipment.
The signals can be received on one or more polarities. In some systems, polarities are usually identified as vertical and horizontal. Each polarization is further divided into an upper and lower frequency band, allowing for four unique 1.2 GHz bands per satellite. Thus, an ODU having an 8 GHz bandwidth is designed to receive two satellite signals. In other systems, the polarizations are circular and thus are either right-hand circular or left-hand circular. The ODU converts the received satellite microwave signals to a lower frequency that can be demodulated by an associated IRD. In traditional systems the RF is converted down to intermediate frequency (IF) bands.
Each polarity contains many transponders, and each transponder contains many channels containing video, electronic program guides (EPGs), data, sound, and other content. For the purposes of this discussion, a channel is a radio frequency transponder signal. Before the advent of the single-cable technology, the entire frequency range of one polarity containing the transponder/video channel which the user wanted to see was switched onto and conveyed through a dedicated cable to the particular user. Each viewing location may want to see a video channel that was transmitted on a different polarity. Since only one polarity can be carried by a cable at one time, a unique cable run was required for each tuner.
In a single-cable system, the ODU down-converts the signals to a number of user-bands (UBs) of smaller bandwidth, for example 40 MHz. Each UB is centered on a fixed center frequency (CF) to which the tuner in a corresponding IRD is assigned (i.e., always tuned). Each UB is generally identified by a unique number. A channel stacking system in a single-cable interface (SCIF) device in the ODU selects a desired transponder containing the video channel that the user wants to view. The desired video channel is frequency shifted to a fixed frequency UB that is sent on the single-cable. The IRD then decodes this video channel for viewing. This fixed frequency UB procedure allows stacking of multiple UBs on a single-cable thereby allowing different viewing selections to be transmitted to multiple viewing locations over the single-cable.
A European industry standard for satellite signal distribution over a single coaxial cable in single dwelling has been promulgated by the European Committee for Electrotechnical Standardization (CENELEC), herein referred to as the CENELEC EN 50494 standard. The CENELEC EN 50494 standard (October, 2007) is generally accepted in at least a wide segment of the electronics industry. One of the processes set forth in the CENELEC EN 50494 standard provides a mechanism for auto-installation of IRDs on a single-cable. This process is intended to be used when one or more IRDs are to be installed or connected to the single-cable to receive satellite television signals. Since each IRD to be installed must coordinate with the ODU which UB the IRD will receive programming, there is a need for communication between the ODU and the IRD.
It should be noted that although the CENELEC EN 50494 standard refers to a single coaxial cable in a single dwelling, the same or similar principles apply to single-cable situations using media other than coaxial cables. In addition, these principles apply to installations in structures other than single dwellings (including installations in structures that are not used as dwellings).
In performing the auto-installation process according to the CENELEC EN 50494 standard, the IRD issues an “ODU_UBxSignal_ON” command in accordance with a format described in the CENELEC EN 50494 standard. In response, the ODU generates a plurality of RF “tones”. One tone is generated at each UB slot center frequency. The IRD that is being installed then scans across the satellite signal band (950-2150 MHz) looking for the tones. According to the standard, the IRD adopts the first UB that it encounters.
In order to maintain a low cost and to maintain backward compatibility, that communication is essentially one-way between the IRD and the ODU. To accommodate this, the CENELEC EN 50494 standard prescribes a Digital Satellite Equipment Communications (DiSEgC™ 1.x) protocol (DiSEgC™ is a trademark of EUTELSAT). This protocol allows signaling between the IRD and ODU. The majority of systems use the DiSEqC 1.x protocol because it provides the basic functionality needed for communication between the ODU and the IRD at the lowest cost.
According to the DiSEgC™ 1.x protocol, the IRD can send tone signal commands to the ODU. However, the ODU can only communicate a “YES” or “NO” message in return. The ODU message is accomplished by sending a tone at the center frequency of the UB to represent a “YES”. A tone 20 MHz above the center frequency represents a “NO.” This makes the automatic negotiation and acquisition of a particular UB by an IRD difficult. That is, the information needed by the IRD to establish the identities of the UBs, coordinate the “understandings” of the ODU and IRD with respect to the operation of each other, and the like, are difficult to communicate using this protocol.
Another problem is that during the auto-installation of an IRD, after the “ODU_UBxSignal_ON” is issued, signals to any other active IRD on the cable may be disturbed. This may result in interference or even loss of video on a channel being watched by viewers using a previously installed IRD. Even worse, the UB that is acquired by the IRD being installed may be the same UB that was assigned to a previously installed IRD. This results in both IRDs using the same UB, which puts each IRD at the mercy of the other for channel selection and other functions. This is clearly undesirable.
As a consequence, the auto-installation process prescribed by the CENELEC EN 50494 standard has generally not been employed in instances in which multiple IRDs are to be installed. Rather, when multiple IRDs are to be installed, an installer must manually assign a unique UB to each IRD. This is time consuming, requires a certain degree of skill on the part of the installer, and may be impractical in multi-dwelling installations.
What is needed, therefore, is a method, apparatus, system, and computer program product for auto-installing IRDs on a single-cable in which multiple IRDs are to be installed. In addition, the method should ensure that signals to previously installed IRDs are not disturbed by the auto-installation process. Still further, in previously assigned UBs are not to be assigned to subsequently installed IRDs during an auto-installation process.